This is a Hunter Douglas PowerView Gen2/Gen3 Idler Assembly Left Side. This piece is great for a replacement part. When do you know you need this to be replaced? When the shade loses its hard limits, also when the shade has trouble coming down the first couple of inches from the top as if the shade gets stuck. Replace this part before it damages your motor. Compatible with the 1 3/8″ Tube for Cassette Only. Idler Assembly Only. Motor is not included.